Snap action valve mechanism for expansible chamber motors with oscillating pistons



Dec. 7, 194s. E. 'ULRicl-f, JR 2,455,628

SNAP` ACTION VALVE MECHANISM FOR EXPANSIBLE CHAMBER MOTORS WITH OSCILLATING PISTONS Filed octfs, 1945 2 sheets-sheet 1 "z I l' lf2 in M42 Dec. 7, 1948. B. ULRICH, JR 2,455,628V

SNAP ACTION VALVE MECHANISM FOR E P NSIBLE CHAMBER MOTORS WITH OSCILLATING STONS 4 Filed 061". 3, 1945 2 Sheets-Sheet 2 INVENTOR.

Armen/fr Patented i Dec. 7, 1948 UNITED .STATES PATENT oEElcE SNAP ACTION VALVE MECHANISM FOR EX- PANSIBLE CHAMBER MOTORS WITH OS- CILLATING PISTONS Bernhard Ulrich, Jr., south nena, Ind., mim to Bendix Aviation Corporation, South Bend, Ind., a corporationof Delaware Application October 3, 1945, Serial No. 620,087

2 Claims. 1

This invention relates generally to fluid-operated motors and more particularly to hydraulically actuated windshield wipers for vehicles.

An object of the inventionlies in the provision of a wiper mechanism for a vehicle which may be regulated to operate at constant speed independent of the engine speed.

A further object of the invention resides in the provision of a fluid motor arranged in a hydraulic system for operating a windshield wiper.

A still further object lies in the provision of an improved hydraulically actuated motor for windshield wipers having a valve responsive to an oscillating member of the motor for reversing the direction of said motor.

Another object of the invention is to provide a uid motor of novel construction for the actuation of a windshield wiper blade, a machine tool, or any similar part to be moved over a restricted range of movement. l

Another very important object of the invention resides in the provision of a uid actuated motor having an overcenter or snap action mechanism constructed and arranged to defer valve movement until the driven member of the fluid motor has reached its preselected positions.

The above and other objects and features of the invention will be apparent from the description of the device as illustrated in the accompanying drawings, in which:

Figure 1 is a diagrammatic illustration of a hydraulic system incorporating my invention;

Figure 2 is a longitudinal sectional view, partly in elevation, of a` iiuld motor constructed in accordance with the present invention;

Figure 3 is a view in section taken on the lines 3--3 of Figure 2;

Figure 4 is a view in section taken on the lines 4 4 of Figure 2;

Figure 5 is a diagrammatic illustration of the fluid connections to the oscillatable member; and

Figures 6, 7, 8 and 9 show the relationship of parts of the valve operating mechanism for various positions of the valve.

Referring now to Figure 1 of the drawing, the reference numeral II) indicates the device of the invention and is connected to an accumulator II' which stores fluid under a predetermined presi upper limit value. During the by-passing period sure. A pump I2 connected to a vehicle engine,

not shown, puts the fluid under pressure in the the pump merely circulates the iiuid through the unloading valve. A` check valve I6 is connected into the system between the pump and the accumulator to prevent the leakage of the uid from the accumulator back to reservoir I8. A valve I9 is disposed in the system between the accumulator and the wiper mechanism to control the fluid to the latter.

The uid motor I0 includes a body or main housing 20 having a closed end 22 and an open end 24 threaded at 2B to receive an end plate or bushing 28. The closed end of the housing is drilled at 38 and 82 to form inlet and outlet ports respectively which communicate with the interior of the housing 20. A ange 34 integral with the housing at the open end thereof is drilled at 38 to receive any form of fastening means, suchas bolts, not shown, for securing the fluid motor into position. The end plate 28 is drilled at 38 and 40 to accommodate a stepped shaft 42, one end of which extends into the interior of housing 20 and the other end of which protrudes exteriorly of said housing. The end plate 28 is counterbored at 44 to receive a sealing element 46 which seals the interior of the housing to atmosphere.

A valve retaining member or valve housing 48 is secured to the interior of the main housing 20 and is bored at 58 to form a bearing for that end of shaft 42 which extends 'interiorly of said main housing. The valve housing 48 is drilled or bored at 52 to receive a slidable valve element E4 having lands 88 and i8 which form a sliding fit with the bore 52. A passage 60 in the main housing 20 and valve housing 48, communicates the inlet 80 with the bore 52 and passages 62 and 84 in the valve housing 48. A ring-like element 88 is disposed in the housing 20 between the end plate 28 and the valve housing 48, and is held securely in place by the end plate 28 ywhich is screwed into the main housing in abutting relationship with the ring element. The end plate 28 is grooved at 88 to receive a seal 18 to provide a liquid-tight connection, between chamber 12, formed in part by the ring-like element 88, and atmosphere. The end plate 28 and valve housing 48 form end walls for the chamber 12. A block` 18 is drilled at 18 and 88 to form passages registering with the passages 62 and 84 respectively for connecting the interior of the chamber 12 to the 4bore 52. The block is held in position by pin 82 which insures the proper alignment. of the corresponding passages in the valve housing and block. The block 18 is curved at 04 to follow the contour of the shaft 42 to form a liquid-tight relationship between the block and shaft.

A vane or oscillating member 'Il is disposed in the chamber 'l2 and is carried by the shaft 42. The vane is fixed to the shaft 42 by a bolt 0l which threadedly engages the shaft.

The end of the shaft 42 which extends interiorly of the housing 20 has a reduced end portion machined at 92 to engage a mating portion 03 of a cam member 04. The cam member is provided with an arcuate rib 00. having a center of rotation coincident with the longitudinal axis of the shaft 42.

For changing the position of the valve I4 to control the flow of fluid to chamber 12 an actuator 00 is pivotally mounted interiorly of the housing on a pin |00. The actuator includes arm-like members |02 and |04 which engage opposite ends of the valve element 54 for shifting the valve. A lug |06 integral with the actuator is arranged 02 and 'Il and one end of the drilled opening I2. The right side of the vane is open to exhaust or outlet 32 through the passages 00 and 04 and the other end of the drilled opening 52. The direction of now of fluid at this time will be as shown by the arrows in the diagrammatic view of Figure 5.' As soon as the vane has traveled to the end of its stroke to the right the cam 04 will move out of engagement with the lug |04 to allow the ,spring to rotate the actuator to the right to shift the valve 04 to the right to communicate the left side of the vane to exhaust and thereon to be engaged by the arcuate rib of l the cam. A spring |08 has one of its ends fixed to a tab I|0 of the actuator and its other end secured to a tab ||2 of the cam. This arrangement provides a snap action or overcenter control of the valve. Referring to Figure 3, it will be noted that when the tab ||2 is rotated to the right or left, of a plane perpendicular to the paper and passing through points on the tabs at which the spring is attached and also through the center of rotation of the cam, the actuator arms |02 and |04 will accordingly tend to be shifted to the right or left as the case may be.'

In order to defer the operation of the valve, which would otherwise be moved to the right or left as the case may be, immediately after the tab |I2 is moved across center, the lug i00 is engaged by the inner or outer surface of the arcuate rib 96. This engagement of the rib by the'lug |00 allows for a greater angular swing of vane 00 beforereversal of the direction of the vane is achieved. As shown in Figure 6 the lug |08 is positioned with respect to the arcuate rib of the cam so that when the vane is rotated counterclockwise or to the right the outer surface of rib |06 will move into engagement with the lug before the tab ||2 passes through center. The position of the actuator valve, and the relative positions of the cam and lug just after the tab ||2 moves across center, are best shown in Figures 6 to 9. When the vane reaches the end of its stroke in a counterclockwise direction, as shown in Figure 3, the rib of the cam moves away from the lug, to thereby permit the spring |00 to rotate the actuator 98 to the right or clockwise, as shown in Figure 9. Rotating the actuator to the right as aforementioned carries lug |00 with it. After a reversal of direction of the vane to cause the cam to rotate in a clockwise direction or to the left, the inner surface of the rib of cam 54 engages the lug |06, as best shown in Figure 9, a. predetermined time before the tab i|2 crosses over center. This engagement between cam and lug as was the case in the counterclockwise rotation defers rotation of the actuator to the left until the inner surface of the cam rib has moved out of engagement with the lug |00 to thereby allow the spring to urge the actuator to the left to operate -the valve element.

the right side of the vane to the inlet port. With this shift in valve position the vane will now have its right side subjected to inlet pressure and will accordingly be rotated to the left. When the vane has readhed its maximum leftward movement the cam will again move out of engagement with the lug |00 to permit the spring |00 to rotate the actuator to the left to shift the valve 54 to the leftto repeat the cycle of operation. The vane will continue to oscillate as long as the inlet is connected to the fluid pressure.

While I have shown and described one-construction in which the invention may be advantageously embodied, it is to be understood that the construction shown has been selected merely for the purpose of illustration, and that various changes in the size, shape and arrangement of parts may be made witliout departing from the spirit of the invention or the scope of the subjoined claims.l

What I claim as my invention is:

i. A fluid motor comprising a housingvhaving inlet and exhaust ports therein, a shaft in the housing and carried thereby, a member located in said housing andy carried by the shaft, said member being osciilatable between two preselected positions in the housing and having sides spaced apart for subjecting said member to pressure differential to cause the member to oscillate, means communicating the inlet and exhaust ports with the sides of the member and including a valve to be operated when the member reaches any one of the two preselected positions to reverse the application of the fluid pressure acting on the sides of the member to reverse said member, means for operating the valve including a cam fixed to the shaft to rotate therewith, a valve actuator pivotally carried by the housing and constructed and arranged to engage the valve to operate the same, and over-center spring means connecting the cam to the valve actuator for impartinga valve operating force to said valve actuator in response to rotation of the cam, said cam having an annular rib thereon and said valve actuator being equipped with a lug which engages with said rib during rotation ofthe cam to defer operation of the valve until the member has reached one of its preselected positions at which time the lug is disengaged.

2. A fluid motor comprising a housing having inlet and exhaust ports therein, a shaft in the housing and carried thereby, a member located in said housing and secured to the shaft for osmember, means for operating the valve including one of its preselected positions at which time the lug is disengaged.

BERNHARD ULRICH, f Jn.

e ,n 6 A REFERENCES CITED Y The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date e 2,034,086 Clima et al. Mar. 17, 1936 2,310,750 Schnell Feb, 9, 1943 FOREIGN PATENTS V Number Country Date 574,519 Germany e Apr. 13, 1933 

